A more thorough question would have been, "Given northeastern Illinois' water supply constraints, transportation and recreation goals, the ongoing threat of interbasin invasive species movement, and downstream water quality and ecosystem impacts, should we be weighing the costs and benefits of hydrological separation of the Great Lakes and Mississippi River basins, or even re-reversal of the Chicago River itself?" That doesn't roll off the tongue, but it merits asking and answering.

The basic history of the reversal is well known. Before the advent of modern waste water treatment and stormwater management technologies, the majority of Chicago's sewage was being dumped into the Chicago River, which flowed to Lake Michigan. A common quip at the time was the "solution to pollution is dilution." However, then as now, Lake Michigan was the region's primary water source.

Chicago's growth as a national power center was severely hindered by constraints on the availability of clean water, as well as thousands of deaths from cholera, typhoid and other waterborne diseases. The reversal of the Chicago River, in combination with Chicago's role as the hub of a burgeoning national rail network, unleashed the city and region's potential, and we haven't looked back.

The construction of the Chicago Ship and Sanitary Canal (and later the Cal-Sag Channel) linked the Great Lakes and Mississippi River, allowing for the interbasin transfer of barge traffic and other commercial activity. Those shipping lanes remain active to this day; sizable volumes of bulk goods like road salt, sand, and scrap metals make their way throughout the Chicago Area Waterway System (CAWS).

Simply put, in 1900, reversal had two basic goals: to provide clean drinking water for Chicago by moving wastewater away from Lake Michigan; and to establish Chicago as a hub of interbasin freight movement.

With the great exception of the basic operation of CAWS, a lot has changed since 1900. There seems to growing consensus that the following five goals should drive decision-making going forward. It remains to be seen whether hydrological separation or other fundamental changes to CAWS is the only route to achieving these goals.

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1. Improve the water quality and ecosystems of Lake Michigan, Chicago area rivers, and the Mississippi Basin, through better treatment and reduced stormwater and combined sewer overflow effects.

Additionally, it simply isn't true that our region doesn't put dirty water back into Lake Michigan. The capacity constraints of our region's combined sewers mean that in large storm events we're sometimes forced to release a combination of stormwater and untreated sewage directly back into the lake. The largest event in recent history, an immense storm in September 2008, resulted in more than 11 billion gallons of untreated sludge getting dumped in the lake. This argues for more measures to prevent stormwater from entering our region's sewers, and that's where green infrastructure solutions from rain barrels to Eco-Boulevards could play a role.

Another important concern with stormwater runoff is that it actually counts as water we've removed from Lake Michigan. When we reversed the river, we fundamentally altered the hydrology of the region. Before the reversal, all the rain falling in the gray area of the map seen here would have run off into one of our rivers, and ultimately to the lake. Now, the vast majority runs into our sewers, gets treated along with our legitimate sewage, and then is sent downstream. The U.S. Supreme Court considers that stormwater a portion of our diversion, and thus it's part of our potential water supply. In any given year it's between 25 and 30 percent of our actual diversion, and is usually in the vicinity of 500 million gallons a day.

However, because of the river reversal and subsequent diversion rules, we can only take so much —3,200 cubic feet per second. As of 2005, we were at about 88 percent of that. While that means we have some ability to take additional water out of Lake Michigan, additional towns and population growth will move us toward our cap very rapidly. Our economic competitors on the Great Lakes — including Cleveland, Milwaukee, and Toronto — don't have the same constraints, because they send their clean, treated effluent to the lakes, then pump out more. Not tomorrow, and not next year, but within the next century, the fact that our ability to use Lake Michigan water is capped will hurt us.

Moving freight on water is extremely energy efficient. Barges can carry the load of 80 tractor trailers, using far less oil, and emitting far fewer fumes. In a region that loses $7.3 billion a year because of traffic congestion, we need all the alternatives we can get. Most of the goods that come to or leave the Chicago region by barge are bulk "piles" like road salt and coal, rather than separable containers that are often seen double-stacked on trains. Those bulk goods are off-loaded and, over time, trucks come to pick up and remove the material. Until oil costs, emissions-based fees, or other factors make it more cost-effective to move containers by barge than by truck, there may be little opportunity to increase the amount of barge-to-rail traffic. That day is coming, but there are currently few sites where freight can be moved efficiently from rail to barge.

No one contemplating hydrological separation or re-reversal of the river is, or should be, considering an end to water-borne freight movement through the region. Inadvertently putting more trucks on the road is simply a bad idea. Instead, any separation scheme should be coordinated with investments that prepare the region for greater interaction between barges and trains.

4. Sustain growth in recreational and tourism uses of the CAWS.

In 1900, or even in 1971 (the year before the Clean Water Act was passed), the idea of paddling a kayak, sculling, or fishing in the Chicago River would have struck most people as lunacy. However, since 1972, with the consistent achievements of the Metropolitan Water Reclamation District, the quality of the water has increased tremendously. Boat tours and water taxis ply the river, sailboats and motor boats make their way to and from marinas, and there are even a few folks who live on the river. As is the case with freight movement, any separation scenario must account for continued growth in these uses.

The map here shows the spread of zebra mussels; similar maps exist for round gobies, alewives, sea lampreys, and many others. Each of these species, regardless of the severity of their effects on their new environment, inevitably result in millions and millions of taxpayer dollars being spent on species-specific solutions. As an example, the electric barrier being used to slow the advance of the Asian carp (and the second one under construction) won't do a thing for invasive weeds or bacteria that could traverse the CAWS. So, as long as water flows between the basins, there is the risk of species transfer. Unless something is done to eliminate that risk, we'll just keep fighting one species after another.

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We are capable of improving water quality in Lake Michigan, Chicago area rivers, and the Mississippi River Basin. We can increase the region’s available water supply for people, businesses and ecosystems. There are steps we can take to strengthen our position as a freight hub, and we know how to make tourism and recreation easier, safer and more enjoyable. We also know that we have to stop interbasin species transfer, partially so we can stop wasting money on halfway solutions, but primarily so we can protect the lakes and rivers that we value.

Does any single one of these 21st Century goals merit separation or re-reversal? Perhaps not. Do all five, taken together as one vision for the future of our region, justify that kind of investment? Maybe so. That's what we don't know and need to find out.

This is not an Asian carp issue, a disinfection concern, nor a debate of tour boats vs. locks. This is a question about what we want the Chicago region to be in 100 years.

A century ago, they asked themselves the same question, and selected reversal because it was the most efficient of three options to meet the goals of the time. We now face another turning point in the history of the Chicago region, and must be as prudent and patient as our forebears were. Hydrological separation and re-reversal are daunting -- perhaps even intimidating -- but they are not crazy. They may well be the best choice we can make to secure the future we want.

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Comments

There was much discussion about Chicago not disinfecting its water. Makes sense, but what does Chicago do to treat its waste if not disinfect? What other steps are involved, and do other municipalities also follow those steps?

And are there any advantages to not disinfecting, other than modest cost savings?

Thanks Bill. One thing to remember is that the City of Chicago doesn't treat any waste, that's the role of the Metropolitan Water Reclamation District, which is an independent unit of government.

MWRD's treatment filters out solid materials, and then uses microbacteria to consume additional biomass (the sludge produced is then given away for fertilizer production). Disinfection would be a third step, using either chlorination (the chlorine is then removed after killing bacteria) or ultraviolet radiation. Disinfection is required if the water is to be released into recreational waterways, and given that most waterways are recreational, that means most other municipalities disinfect. MWRD actually does some disinfection at some of its smaller plants in the northern suburbs, but not at its largest plant (Stickney, Calumet).

MWRD, however, does not believe that the Chicago waterway systems are conclusively "recreational," and as a result is disputing the need to disinfect at the remainder of its facilities. Other than cost savings, there are no benefits to not disinfecting.

Disinfection would cost money, both for initial capital investment and then ongoing operations, but would lead to cleaner water, and potentially the ability to return some portion of our water to Lake Michigan.

Tours of MWRD facilities are free and available to the public (they prefer groups to individuals), and I highly encourage you to get some friends or peers together and take a look.

Thanks, Josh. I know about MWRD; I used Chicago just for simplicity. Is disinfection pretty much the standard for larger cities these days? Do New York and Philly, for example, disinfect? I'm not arguing against it, just trying to get more context. Whether or not to add this step seems like a pretty significant issue, and I'm trying to get a sense of whether Chicago (OK, MWRD) is living in the dark ages or if there's a rational argument against disinfecting waste water, and in fact we are more typical of metro areas. Thanks

Thanks Bill. Disinfection is the standard. Of the 23 largest wastewater treatment systems in the U.S., only one - ours - does not disinfect. Both of your examples, NY and Philly, definitely disinfect, as do LA, Indianapolis, Milwaukee, and Cleveland. East Chicago and Gary disinfect as well.

Analysis before doing anything is very important. We must remember that when the river was first reversed, the Saint Lawrence Seaway was much less navigable than it is today which meant that we had a longer period when no seabound traffic could flow due to weather and other downstream limitations. Also, remember that most of American exports (grain, timber, etc.) were headed to Europe in those days.

Your reporting on the disinfection issue is correct. The primary issues for MWRD are capital investment and operating costs. For traditional chlorination/dechlorination disinfection, they could easily run over $1 Billion. There is some good news though. Researchers at the WaterCAMPWS at the University of Illinois are developing advanced UV, photocatalytic and hybrid UV/photocatalytic disinfection technologies that would avoid the chlorination/dechlorination steps, and prevent formation of disinfection byproducts, and potentially achieve disinfection at a small fraction of the traditional cost. We hope to deliver a photocatalytic pilot unit to MWRD later this year.

On thing to keep in mind is that disinfecting MWRD's effluent alone may not result in dramatic reductions in pathogens in the CWS, unless it is coordinated with sediment removal to address the well-entrained pathogen population already in the CWS. While I have not seen hard estimates, I have heard discussion that that effort could cost even more than conventional disinfection.

As you insightfully reported, re-separation of the Chicago and Des Plaines River basins would have a significant impact on commerce and bulk commodity shipping. But, if properly planned, this could be a significant driver for reinventing the Joliet region as THE national intermodal hub, with a water/rail/container complex with ready access to the Mississippi basin, CN-owned Elgin, Joliet & Eastern, and BNSF railroads, and Interstates 80 & 55.

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